Apparatus for making plastic tubes



Sheet of 2 Original Filed July 24, 1964 INKENTOR. EM :zy L- VA -yl ATTORNE 7 April 5, 1969 E. 1. WM. 3,438,086

APPARATUS FOR MAKING PLASTIC TUBES Original Filed July 24, 1964 Sheet 2of 2 dig-$1 INVENTOR. E 6K? 1. VFLYT ATTOR N 7 United States Patent MInt. Cl. 329d 23/03 U.S. Cl. 18-5 18 Claims This is a division ofapplication Ser. No. 384,942, filed July 24, 1964 and now U.S. PatentNo. 3,310,621.

This invention relates to an apparatus for making plastic containers andmore particularly to an apparatus for making plastic tube-containers ofthe type commonly used for dispensing cosmetic lotion and the like.

An object is to provide an apparatus of the above type having novel andimproved characteristics.

Another object is to provide an apparatus of the above type in which thethreaded neck of the tube is formed by a neck ring which is transferredfrom the injection station to the blow station and after blowing of thetube is removed from the finished tube and transferred to the injectionstation for reuse.

Various other objects and advantages will be apparent as the nature ofthe invention is more fully disclosed.

The invention utilizes an apparatus of the general type disclosed in mycopending application, Ser. No. 353,004 filed Mar. 18, 1964 whichincludes a blow core on which a parison is injected in a parison die.The blow core is then retracted axially into a blow mold wherein theparison is blown into the form of the finished bottle or the like. Afterblowing, the blow core is further retracted from the blow mold into aconditioning chamber, the blow mold with the bottle therein is shiftedlaterally out of the path of the blow core for cooling and the bottle isdischarged therefrom while the blow core is advanced into the parisondie for the injection of the next parison.

The present invention applies particularly to the making of an objectsuch as a tube container having a neck which is considerably smallerthan the tube and which has an extremely small opening such that itcannot be formed by the usual molding operation.

In accordance with the present invention, the tube is formed with theneck portion disposed at the end of the blow core adjacent the injectionnozzle. An internally threaded neck ring is secured in the parison dieadjacent the end of the blow core and so positioned that the plastic isinjected through the neck ring to form the parison. The open end of thetube, that is, the end opposite the neck, is formed by a sleeveregistering with the parison die and movable with the blow core from theparison die into the blow mold for holding the parison during blow-After the parison has been formed by injection, the parison die isopened sufficiently to release the neck ring which is retracted with theblow core into the blow mold wherein the neck ring is again clampedduring the blowing step. During the transfer, the neck ring is carriedby the plastic of the neck portion of the tube and may be furthersupported magnetically by means of a magnet in the end of the blow core.

After the blowing step, the blow core and sleeve are retracted and theblow mold is shifted transversely into ejecting position. In thisposition a neck ring carrier is advanced to contact the exposed surfaceof the neck ring and support the same. The blow mold is then opened torelease the tube and to provide clearance for a transfer mandril andclamp which then descends to enter the formed tube from its open end.The transfer mandril may carry a punch to pierce the plastic of the neckto size or to form the opening therein. The clamp then grips 3,438,086Patented Apr. 15, 1969 the walls of the tube while the neck ring carrieris rotated to unscrew the neck ring from the threaded exterior of theneck of the tube. The finished tube is then blown off of the mandril andthe neck ring carrier deposits the neck ring on a carriage whichtransfers it into the parison die for the start of the next injectioncycle.

The nature of the invention, the details of the apparatus and thefeatures of operation will be better understood from the followingdetailed description, taken in connec tion with the accompanyingdrawings in which a specific embodiment has been set forth for purposesof illustration.

In the drawings:

FIG. 1 is a vertical section through an apparatus embodying theinvention showing the blow core in injection position and the blow moldin discharge position;

FIG. 2 is a similar section showing the parison die station on a largerscale;

FIG. 3 is a section similar to FIG. 1 showing the blow mold in blowposition with the blow core removed after blowing;

FIG. 4 is a section through the blow mold in release position taken onthe line 4-4 of FIG. 1 showing the transfer mandril inserted into thetube;

FIG. 5 is an enlarged vertical section showing a portion of the transfermandril, neck ring and carrier and FIG. 6 is a prospective detail viewof the neck ring and carrier.

Referring to the drawings in more detail, the apparatus is shown ascomprising a blow core 10 having a cylindrical surface 11 and an endsurface 12 adapted to form the inner walls of a parison die station andcooperating with outer parison die members 13 to form the sides of aparison 14. A neck ring 15 having a threaded inner surface 16 has aperipheral groove 20 which is clamped by a flange 21 on the parison diemembers 13. An injection nozzle 22 having an injection opening 23registering with the neck ring 15 is mounted in a fixed frame 24 and issupplied with plastic for molding from a suitable source, not shown. Theblow core 10 is carried by a stem which extends upwardly to a cross head31 by which the blow core is actuated. The upper end of the blow core 10is tapered outwardly at 32 and the outer parison die members 13 aresimilarly tapered at 33 to register with a sleeve 34 which is slidablymounted on the stem 30 and has an end shoulder 35 registering with asimilar shoulder 36 on the blow core 10 to provide an opening for blowair when the sleeve 34 is retracted. The stem 30 is formed with an axialair passage 37 communicating with the opening between the shoulders 35and 36 for supplying blow air to the interior of the parison. The sleeve34 has a key 40 to prevent turning and is actuated by a pinion 41 whichin turn is driven by a rack 42 attached to a rod 43 which is actuated bya suitable piston, not shown. An outer sleeve 45 registers with theparison die to form the end rim 46 of the parison. This outer sleeve 45is carried by a cross head 47 by which it is raised and lowered asrequired.

The cross head 47 also carries a cylinder sleeve 50 which is adapted totelescope within a sleeve 51 carried by the cross head 31 and whenextended to form a conditioning chamber for the blow core. The neck ring15 is preferably make of magnetic material and a permanent magnet 17 isdisposed in the end of the blow core 10 in a position to assist insupporting the neck ring when the blow core is retracted with theparison thereon and with the plastic neck of the injected parisonretained between the blow core and the neck ring.

The blow mold comprises a pair of parts having a cavity 61 adapted toform the tube and having end walls formed with a flange 62 adapted toenter the groove 20 in the neck ring for clamping the same in placeduring the blowing step. The lower surface of the neck ring is formedwith lugs 63 which are adapted to enter recesses 64 in the upper surface65 of a neck ring carrier 66 when the latter is in contact with the neckring as shown in FIG. 1. The neck ring carrier 66 is raised and loweredby suitable means, not shown. The carrier 66 extends through anelongated slot 71 in a carriage 72 which is shiftable transversely by apiston not shown. The bottom surface of the neck ring is adapted to seatwithin the groove 73 of the carriage 72 so that the neck ring istransferred thereby from the carrier to the parison die. After the neckring 15 has been clamped by the parison die as above described, thecarriage can be returned to position to register with the carrier 66.

Suitable means, such as a train of gears, is provided to rotate thecarrier 66 so as to unscrew the neck ring 15 from the threaded neck ofthe finished tube. The gear train may be actuated by suitable means suchas a motor 81.

A transfer mandril 82 is disposed in a position to enter the open end ofplastic tube in the blow mold while the blow mold is in the transferstation with the neck ring 15 engaged and supported by the neck ringcarrier 66. The transfer mandril 82 has a peripheral surface 83 adaptedto fit within the interior of the plastic tube and at its end carries apunch 84 which is adapted to pierce the plastic wall of the neck of thetube to form a neck opening 85. The neck ring carrier 66 is formed withan opening 86 to receive the plug 87 which is punched out of the plasticneck by the punch 84. Plug 87 is formed only if the entire end surfaceof the neck is used for entry of plastic into the parison mold duringthe injection step. Depending upon the shape and size of the neckopening, it is frequently possible to inject the plastic into the endperiphery of the neck, or only into part of the neck opening. In suchinstances neck opening is either not at all, or only partly filled withplastic and therefore either no plug or only part of the plug 87 isformed and punched out.

The transfer mandril 82 is carried by a stem 90 which is actuated by acylinder 91 for raising and lowering the mandril. The stem 90 carries asleeve 92 which is slidable axially on the stem 90 between an adjustablenut 93 on the stem and the upper surface of the mandril 82. The clampactuator ring 95 having an outer flange 96 is slidably mounted on thesleeve 92 and is spring pressed downwardly by a spring 97 which seatsagainst a retainer ring 98 which is threaded onto the sleeve 92 forpurposes of adjustment. The actuator ring 95 is held by a lower flange99 on the sleeve 92. The outer flange 96 of the actuator ring 95 carriesa set of pins 100 which are V adapted to actuate the clamp members to bedescribed. A set of clamp members 101 carried by a clamp ring 102 areadapted to be advanced radially inward into clamping engagement with theouter surface of the plastic tube by means of the pins 100 when the pinsare advanced downwardly with respect to clamp members 101. The clampcarrier 102 is mounted for vertical movement on rods 103 which areslidable in supports 104 and are formed at their upper ends withshoulders 105 which limit their downward movement. The fiange 96 extendsdownwardly through a bore 106 in the clamp carrier ring 102 and isformed with an outer shoulder 107 which is adapted to engage a shoulder108 on the carrier ring 102 for lifting the latter. The transfer mandril82 is formed with an axial air passage 110 for compressed air which isapplied at a suitable time to blow the formed plastic tube from thesurface of the mandril.

In the operation of this apparatus the blow core 10 is advanced into theparison die 13 as shown in FIG. 1 with a neck ring 15 clamped by the diemembers 13 and the outer sleeve 45 is brought into registration with theparison die. If the tube to be produced is to have an open end ofpredetermined cross section, as for example threaded or otherwisecontoured, then the outer sleeve 45 may of course contain a suitable diemember for that purpose, similar to the neck ring described in mycopending application above mentioned. The plastic is then injected toform the parison 14. The parison die members 13 are then opened torelease the neck ring 15 and the parison 14. The blow core 10 isretracted with the formed parison thereon and with the neck ring 15carried by the neck of the parison and by the permanent magnet 17. Theouter sleeve 45 and the blow core 10 are then retracted together intoblow position and the blow mold 60 is closed therearound. The neck ring15 is clamped in the blow mold 60 and the sleeve 3 is retracted to formthe blow opening after which the blow air is supplied for blowing theparison into the blow mold cavity 61.

After blowing, the blow core 10 and the outer sleeve 45 are retractedfrom the rim 46 of the blown tube and the blow core 10 may be furtherretracted into the conditioning chamber formed by the cylinder sleeve50, wherein it is cooled or otherwise processed as by application of acoating, for the next injection step.

The blow mold 60 with the blown tube therein is then shiftedtransversely out of the path of the blow core and into the dischargeposition, the post 70 is raised to cause the neck ring carrier 66 toengage and support the neck ring 15. The blow mold 60 is then opened andthe transfer mandril S2 is advanced to locate the transfer device inrelation to the blown tube and, if necessary, to cause the punch 84 topunch out the neck opening 85 in the neck of the formed tube. The clampmembers 101 then close to grip the tube and the post 70 is rotated tounscrew the neck ring 15 from the threaded neck of the formed tube. Inthe production of tubes whose neck carries no threads, but is forexample, instead adapted to carry a slip-on closure, unscrewing of theneck ring is of course not required. Instead, post 70 merely serves toremove the neck ring downward and may be for that purpose equipped witha magnet, better to hold the neck ring. The post 70 is then retracted todeposit the neck ring 15 on the carriage 72 after which the formed tubeis blown off the transfer mandril. While being carried by post 70, theneck ring may be cooled or otherwise treated for the next injectioncycle, by a suitable fluid spray or the like 112, arranged in the pathof retraction of the neck ring. The carriage 72 then shifts to theinjection position where the neck ring is again clamped by the parisondie 13 after which the carriage returns to transfer position and thecycle is repeated.

The above described apparatus provides means for die molding and blowingan object having a small neck opening in a continuous cycle wherein onetube is being discharged from the blow mold and its neck ring removedwhile a second parison is being injected in the parison die. While aspecific mechanism has been shown and de scribed, it is apparent thatvarious changes and modifications may be make therein according to thespecific object to be formed.

What is claimed is:

1. Apparatus for forming a hollow object of organic plastic materialcomprising a parison die including an outer die member and a blow corehaving a free end extending into said outer die member to form a parisoncavity, and a blow mold spaced from said parison die and having a cavityin which said hollow object is to be blown, characterized by a confiningmember adapted to form a shaped end of said parison which projectsbeyond the end of said blow core, said confining member being carried byand detachable from said outer die member, means molding said parison onsaid blow core in said parison die with a shaped end portion extendingbeyond said blow core and confined in said confining member, meansreleasing said confining member from said outer die member andretracting said blow core with the formed parison thereon and with theconfining member supported by the plastic of said shaped end portionwhile the parison i supported by said blow core, from said parison dieinto said blow mold, means securing said confining member in said blowmold and blowing said parison to form said hollow object, meansreleasing said confining member from said blow mold and removing saidconfining member from said shaped end of said object.

2. Apparatus as set forth in claim 1 further characterized by meansreturning said confining member to said parison die and securing thesame therein for the next molding cycle.

3. Apparatus as set forth in claim 1 further characterized by means forintroducing the plastic material into the confining member to form theshaped end and to fill the parison cavity.

4. Apparatus as set forth in claim 1 further characterized in that asecond confining member is disposed in registration with the parisonmold cavity to form with the blow core a shaped rim at the open end ofthe parison, the last confining member being shiftable with the blowcore from the injection position into the blow position for confiningsaid rim during blowing.

5. Apparatus for forming a hollow object of organic plastic materialcomprising a parison die including an outer die member and a blow corehaving a free end extending into said outer die member to form a parisoncavity, and a blow mold spaced from said parison die and having a cavityin which said hollow object is to be blown, characterized by a pair ofconfining members adapted to form shaped ends of said parison, meansmolding said parison on said blow core in said parison die with theshaped end portions confined in said confining members, means retractingsaid blow core with the formed parison thereon and with the confiningmembers in place on and confining said shaped ends of said parison fromsaid parison die into said blow mold, means blowing said parison in saidblow mold to form said hollow object with the confining members in placeto form the shaped ends of the hollow object and means removing theconfining members from said shaped ends.

6. Apparatus as set forth in claim 1 including a transfer mandriladapted to enter and position said hollow article for removal of saidconfining member.

7. Apparatus as set forth in claim 6 wherein said transfer mandrilincludes a punch adapted to pierce the end of said tube for forming anend opening therein.

8. Apparatus as set forth in claim 1 including clamping means disposedto grip said hollow article during the removal of said confining member.

9. Apparatus as set forth in claim 1 wherein at least two confiningmembers are included, one of said confining members being disposed insaid parison die while the other of said confining members is intransfer position.

10. Apparatus as set forth in claim 1 including cooling means disposedto cool said confining member during its transfer to said parison die.

11. Apparatus as set forth in claim 1 wherein said confining member ismade of magnetic material and a permanent magnet is disposed in saidblow core within the range of magnetic influence of said confiningmember.

12. Apparatus as set forth in claim 1 in which said confining member isinternally threaded to form exterior threads on the shape end of saidhollow article and means is provided for rotating said carrier forunscrewing said confining member from the formed shaped end of saidhollow article.

13. Apparatus as set forth in claim 1 including a carriage shiftablebetween said carrier and said injection die, said carrier being adaptedto deposit said confining member onto said carriage.

14. Apparatus as set forth in claim 1 in which a sleeve is disposed inregistration with said parison mold cavity to form with said blow core arim at the open end of said parison, said sleeve being shiftable withsaid blow core from injection position into blow position.

15. Apparatus as set forth in claim 14 having a cylinder sleeveassociated with said first sleeve and means retracting said blow coreinto said cyilnder sleeve for conditioning after the parison has beenblown.

16. Apparatus as set forth in claim 1 in which a transfer mandril isprovided, external clamping members are associated with said mandril andmeans is provided to clamp said hollow article between said clampingmembers and said mandril to hold the hollow article during the removalof said confining member.

17. Apparatus as set forth in claim 1 in which said confining member isformed with a positioning groove and said parison die and said blow moldare provided with positioning flanges adapted to register with saidgroove for positioning and securing said confining member in place.

18. Apparatus as set forth in claim 1 in which a carriage having agroove adapted to receive said confining member is disposed to shiftbetween said parison die position and a transfer position, said carrieris disposed on a retractable post which extends through said groove intoreceiving position, said post being retractable to deposit saidconfining member on said carriage.

References Cited UNITED STATES PATENTS 3,347,965 10/1967 Valyi.

3,364,520 1/ 1968 Hestehave.

FOREIGN PATENTS 563,595 1/1958 Belgium.

WILBUR L. MCBAY, Primary Examiner.

1. APPARATUS FOR FORMING A HOLLOW OBJECT OF ORGANIC PLASTIC MATERIALCOMPRISING A PARISON DIE INCLUDING AN OUTER DIE MEMBER AND A BLOW COREHAVING A FREE AND EXTENDING INTO SAID OUTER DIR MEMBER TO FORM A PARISONCAVITY, AND A BLOW MOLD SPACED FROM SAID PARISON DIE AND HAVING A CAVITYIN WHICH SAID HOLLOW OBJECT IS TO BE BLOWN, CHARACTERIZED BY A CONFIDINGMEMBER ADAPTED TO FORM A SHAPED END OF SAID PARISON WHICH PROJECTSBEYOND THE END OF SAID BLOW CORE, SAID CONFIDING MEMBER BEING CARRIED BYAND DETACHABLE FROM SIAD OUTER DIE MEMBER, MEANS MOLDING SAID PARISON ONSAID BLOW CORE IN SAID PARISON DIE WITH A SHAPED END PORTION EXTENDINGBEYOND SAID BLOW CORE AND CONFINED IN SAID CONFINING MEMBER, MEANSRELEASING SAID CONFINING FROM SAID OUTER DIE MEMBER AND RETRACTING SAIDBLOW CORE WITH THE FORMED PARISON THEREON AND WITH THE CONFINING MEMBERSUPPORTED BY THE PLASTIC OF SAID SHAPED END PORTION WHILE THE PARISON ISSUP-